claude-noether
662f8874ba
Adds VAProfileH264High10 and VAProfileHEVCMain10 to the libva-v4l2-request
backend. RK3399 rkvdec emits decoded frames as V4L2_PIX_FMT_NV15 (4 × 10-bit
values packed in 5 bytes per element); VAAPI consumers receive standard
VA_FOURCC_P010 via a new userspace unpack in copy_surface_to_image.
VP9 Profile 2 explicitly NOT added — RK3399 rkvdec kernel ctrl table
caps at V4L2_MPEG_VIDEO_VP9_PROFILE_0 (rkvdec.c::rkvdec_vp9_ctrl_descs).
Touchpoints (per Phase 5 sonnet-architect review amendments):
- include/drm_fourcc.h: define DRM_FORMAT_NV15 (vendored libdrm lacks it)
- src/nv15.{c,h}: NV15 → P010 plane unpack (LSB-first, per
Documentation/userspace-api/media/v4l/pixfmt-nv15.rst)
- src/video.c: NV15 entry in formats[] (else NULL-deref on video_format_find)
- src/codec.c: pixelformat_for_profile cases for Hi10P + Main10
- src/config.c: enumeration, validation, entrypoints, RT_FORMAT_YUV420_10
advertisement for 10-bit profiles
- src/context.c: per-profile CAPTURE pix_fmt (NV12/NV15), 10-bit synthetic
SPS (bit_depth_luma_minus8=2), video_format invalidation on bit-depth
transition (sibling to iter38 device-switch invalidation), is_10bit flag
- src/surface.c: RT_FORMAT_YUV420_10 admission, NV15 fourcc on PRIME export
- src/image.c: P010 reporting in DeriveImage + QueryImageFormats,
P010-aware sizing in CreateImage, NV15 → P010 unpack call in
copy_surface_to_image (gated on is_10bit + image.format.fourcc == P010)
- src/picture.c: 4 switch blocks route Hi10P/Main10 to existing H264/HEVC
per-codec paths
- src/request.h: MAX_PROFILES bump 11 → 13, driver_data->is_10bit flag
Scope: COPY path (vaGetImage / vaDeriveImage) only. Standard ffmpeg-vaapi
hwdownload, mpv vaapi-copy, and any consumer using vaGetImage works
end-to-end. PRIME-path consumers that only know NV12/P010 must use the
COPY path; PRIME consumers aware of NV15 (panfrost-Mesa et al.) get the
correct fourcc on RequestExportSurfaceHandle. PRIME-side P010 emission is
follow-up scope (would need DRM_FORMAT_P010 + per-plane unpack into a
GPU-accessible buffer).
Compile-tested on boltzmann (aarch64 native, gcc 15.2.1, libva 1.23.0,
libdrm 2.4.133): clean build, .so produced, 0 new warnings.
Phase 0/2 evidence: linux-mmind-v7.0 drivers/media/platform/rockchip/rkvdec.
rkvdec_h264_decoded_fmts[] and rkvdec_hevc_decoded_fmts[] both list NV15;
ctrl tables cap at HEVC MAIN_10 and H264 HIGH_422_INTRA (Hi10P < cap, not
in menu_skip_mask). image_fmt resolution (rkvdec-h264-common.c:196,
rkvdec-hevc-common.c:467) dispatches on bit_depth_luma_minus8 only.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
v4l2-request libVA Backend
About
This libVA backend is designed to work with the Linux Video4Linux2 Request API that is used by a number of video codecs drivers, including the Video Engine found in most Allwinner SoCs.
Status
The v4l2-request libVA backend currently supports the following formats:
- MPEG2 (Simple and Main profiles)
- H264 (Baseline, Main and High profiles)
- H265 (Main profile)
Instructions
In order to use this libVA backend, the v4l2_request driver has to
be specified through the LIBVA_DRIVER_NAME environment variable, as
such:
export LIBVA_DRIVER_NAME=v4l2_request
A media player that supports VAAPI (such as VLC) can then be used to decode a video in a supported format:
vlc path/to/video.mpg
Sample media files can be obtained from:
http://samplemedia.linaro.org/MPEG2/
http://samplemedia.linaro.org/MPEG4/SVT/
Technical Notes
Surface
A Surface is an internal data structure never handled by the VA's user containing the output of a rendering. Usualy, a bunch of surfaces are created at the begining of decoding and they are then used alternatively. When created, a surface is assigned a corresponding v4l capture buffer and it is kept until the end of decoding. Syncing a surface waits for the v4l buffer to be available and then dequeue it.
Note: since a Surface is kept private from the VA's user, it can ask to directly render a Surface on screen in an X Drawable. Some kind of implementation is available in PutSurface but this is only for development purpose.
Context
A Context is a global data structure used for rendering a video of a certain format. When a context is created, input buffers are created and v4l's output (which is the compressed data input queue, since capture is the real output) format is set.
Picture
A Picture is an encoded input frame made of several buffers. A single input can contain slice data, headers and IQ matrix. Each Picture is assigned a request ID when created and each corresponding buffer might be turned into a v4l buffers or extended control when rendered. Finally they are submitted to kernel space when reaching EndPicture.
The real rendering is done in EndPicture instead of RenderPicture because the v4l2 driver expects to have the full corresponding extended control when a buffer is queued and we don't know in which order the different RenderPicture will be called.
Image
An Image is a standard data structure containing rendered frames in a usable pixel format. Here we only use NV12 buffers which are converted from sunxi's proprietary tiled pixel format with tiled_yuv when deriving an Image from a Surface.